Intrapartum fetal surveillance is routinely offered to reduce the risk of both adverse neonatal outcomes and unnecessary emergency cesarean delivery. Newer methods of fetal surveillance have been developed, but it isn't clear how they compare with simple intermittent auscultation of the fetal heart. Researchers conducted a systematic review and network meta-analysis to evaluate the effectiveness of all available fetal surveillance methods in improving maternal and neonatal outcomes.

They included 33 randomized trials (120,151 patients), two-thirds of which comprised patients with high-risk pregnancies. Ten types of fetal surveillance were evaluated, including intermittent auscultation, cardiotocography alone or in combination with computer-aided cardiotocography, fetal scalp blood lactate sampling, fetal scalp blood pH sampling, fetal pulse oximetry, and fetal heart electrocardiogram.

Compared with other surveillance methods, intermittent auscultation reduced the risk of emergency cesarean deliveries, including those due to suspected fetal distress. All types of surveillance had a similar effect on neonatal acidemia, admission to the neonatal ICU, Apgar score, and perinatal death.

Few of the included trials reported on key long-term neonatal outcomes, the researchers note, and the quality of the older trials wasn't the same as that of newer studies. Also, several potential effect modifiers, such as progress in labor, weren't considered, and most of the trials were underpowered to detect rare adverse neonatal outcomes.